>I am REALLY new to ceramics but am really enjoying teaching and
>learning along with my students.
>So here's my question -- if a student has a piece that has already
>glaze-fired, and she forgot to use the clear glaze on top, can she
>re-glaze it and then glaze fire it again?
In most cases this works fine.
If the glaze firing has left the clay harder and less porous, you have to try harder to get enough glaze thickness. If this is a problem, use a thicker glaze mix or heat the piece a bit for glazing. I thicken glaze by pouring off the top water before stirring it (then pour the same water back in when finished). In rare cases where the piece has been fired to stoneware temperatures such as cone 6, the piece explodes if it is re-glazed and fired before all the glazing moisture has been dried out. This is probably not a problem for the cone 06, 05, and 04 glaze firings.